Computerized process control systems have come into widespread use in the manufacture of chemicals and pharmaceuticals. Such systems substantially reduce the manual labor which has previously been required and further tend to reduce the possibility of errors in such operations. However, the process control computer system and its software must be validated to ensure that the required manufacturing sequences are properly carried out. To produce such validation, it is often necessary to utilize a simulator system which reproduces the actions of the actual process hardware so that, for effective purposes, the computerized control system is running the various process operations for which it was designed. The simulation system is often available prior to the actual process hardware so that the process control software can be developed concurrently with the process hardware. The use of a simulator reduces the need for maintaining and operating expensive hardware, and the consuming of expensive materials. In addition, the simulator can be used for training purposes.
The computer control and software associated with a simulation system must validated in order to ensure their proper operation. Such validation has, in some cases, proven to be more expensive than validation of the process control system itself. This increased expense is attributable to the fact that the simulation system must not only demonstrate proper system operation, but must also include expected failure modes as well. Further, the validation of a simulator system may be more difficult than validating the process control system.
The pharmaceutical industry is regulated by the U.S. Food and Drug Administration. Regulations of this agency require that there be detailed documentation for computer systems which are to be used in the production of pharmaceutical products. The term "validation" is defined as the documentation which shows that a computer system has performed as it is intended to perform. Validation includes a variety of documentation such as application source code, installation information, design specifications, results of testing, print-outs, etc. A key requirement in the validation is documentation which shows that the simulator is properly generating the desired conditions, both normal and error conditions. The processes required for each product must be separately documented.
In view of the requirement to validate simulator and computer processes in the pharmaceutical industry, and the difficulty of producing proof that a computer program works as intended, there exists a need for a method to document the operation of the system for validation purposes.